Terik Daly

We use hypervelocity impact experiments to measure how much water gets delivered by impacts. The answer? Up to about a third of the impactor's water is trapped in and near the crater under conditions typical of the main asteroid belt and early planet formation. Moreover, we show that this water is trapped in a combination of impact-generated glasses and impact breccias, which may have contributed to the surprisingly early accretion of water in the inner solar system.

Published in Science Advances as "The delivery of water by impacts from planetary accretion to present ".

Read about the work in the New York Times.

During impacts on Earth, tiny amounts of the impacting asteroid or comet can be mixed into melted Earth rocks. We can sniff out these tiny "fingerprints" using geochemical tools like osmium isotopes. In collaboration with colleagues at the UT Austin and the University of New Brunswick, we used osmium isotopes to search for meteoritic signatures in impact melt rocks from two Canadian craters: East Clearwater and West Clearwater. The results surprised us!

Published in Geochimica et Cosmochimica Acta as "Contrasting meteoritic signatures within the Clearwater East and Clearwater West impact structures: The view from osmium isotopes​".

All impacts are oblique to some degree; a 45-degree angle impact is the most probable. We investigated how variables such as impact speed, impact angle, projectile type, and target type affected the distribution and physical state of impactor survivors. The results motivate a new strategy for the recovery of samples during hypervelocity impacts.

Published in Meteoritics and Planetary Science as "Projectile preservation during oblique hypervelocity impacts".

Hypervelocity impact experiments, coupled with scaling calculations, predict extensive impactor contamination on Ceres. We explore how the bulk composition of Ceres affects the character of projectile remnants.

Published in Geophysical Research Letters as "Predictions for impactor contamination on Ceres based on hypervelocity impact experiments".

Click here for the press release. This paper was also featured in Eos.

My coauthors and I show that that Vesta accretes large quantities of meteoritic debris, largely hosted within the glassy melt breccias. The experiments at the core of this work, which were performed at the NASA Ames Vertical Gun Range, provide insight into how dark material is delivered to Vesta and reveal the physical state of the projectile component.

Published in Icarus as "Delivering a Projectile Component to the Vestan Regolith".

Current dust accelerators can only accelerate electrically-conductive particles. We show that electrospray charges minerals and astrophysical ices without the need for conductive coatings. This opens new avenues for experiments with realistic planetary materials, potentially transforming laboratory studies of cosmic dust.

Published in Planetary and Space Science and Earth, Planets, and Space as "Electrospray charging of minerals and ices for hypervelocity impact research" and "A novel particle source based on electrospray charging for dust accelerators and its significance for cosmic dust studies​", respectively.

Many asteroids appear to be "rubble piles" of blocks, boulders, and debris bound by gravity. (The asteroid Itokawa is one example.) Along with others at APL, Sandia National Labs, and NASA Johnson Space Center, we investigated how such targets influence the cratering process. The experiments yielded results that are difficult to reconcile with theoretical predictions for how craters grow. This implies that cratering on rubble-pile asteroids might be controlled by the very early-time coupling between projectile and target.

In review at Icarus.